Lifting light with more reps can be effective... but it takes MUCH longer to reach fatigue, which is the ultimate goal of strength training. What it WON'T do is "keep you from getting bulky" - you'll hear that a lot in the gym from people who don't know any better. ;) The truth of the matter is, unless you are genetically predisposed to do so, train like a body builder (with extreme weights and time) and EAT like a body builder (huge calorie surpluses) you can't bulk up. In other words... it's not going to happen by accident. ;)
Since I doubt you're fabulously wealthy with tons of time to waste, you want to get the most bang for your time buck; so lift heavy, and aim to fatigue your muscles (where you can't complete another rep in good form) in 12 or fewer reps... the fewer the better.
If you can do 15 or more... you're not lifting heavy enough!
Writer, mother, wife, and breadwinner. I love to run, but running doesn't love me, so I'm switching to my low-impact bike.
I'm not pregnant, just fat: My blog. fatnotpregnant.blogspot.com/
| current weight: 190.6